Chimpanzees who congregated together had more bacteria species suggesting friends passed on helpful microbes

Spending time with friends could be good for your health because they are likely to pass on friendly bacteria, scientists believe.

A study of 40 chimpanzees in Tanzania found that when the primates congregated together when food was plentiful in the rainy season they had 25 per cent more bacterial species in their guts than in the dry season when they forced to travel further afield.

Friendly bacteria live in the gut where they help break down food, synthesize vitamins, train the immune system and fight infections. Reduced gut microbial diversity in humans has been linked to obesity, diabetes, Crohn’s and other diseases.

“The more diverse people’s microbiomes are, the more resistant they seem to be to opportunistic infections.”

Andrew Moeller, University of California

Although it was previously though that close contact with others raises the risk of catching germs and getting ill, the new research suggests that it also allows the transmission of good microbes, say researchers at the University of California, Berkeley, and Duke University in the US.

“The more diverse people’s microbiomes are, the more resistant they seem to be to opportunistic infections,” said lead author Andrew Moeller.

Moeller and colleagues analysed the bacterial DNA in droppings collected from 40 chimpanzees between 2000 and 2008. The chimpanzees ranged in age from infants to seniors.

The researchers identified thousands of species of bacteria thriving in the animals’ guts, many of which are also commonly found in humans, such as species of Olsenella and Prevotella.

Chimps pass on helpful bacteria through grooming

The team then combined the microbial data with daily records of what the animals ate and how much time they spent with other chimps versus alone.

Moeller and colleagues analyzed the bacterial DNA in droppings collected from 40 chimpanzees

“Chimpanzees tend to spend more time together during the wet season when food is more abundant,” said Duke University research scientist Steffen Foerster, who co-authored the study. “During the dry season they spend more time alone.”

Each chimpanzee carried roughly 20 to 25 percent more bacterial species during the abundant and social wet season than during the dry season.

Previous research has suggested that people who are lonely are more likely to die earlier but scientists thought it was because they did not have friends or partners to look after them and encourage them to stay healthy.

“One of the main reasons that we started studying the microbiomes of chimpanzees was that it allowed us to do studies that have not or cannot be done in humans,” said study co-author Howard Ochman of the University of Texas at Austin.